Musannaf Ibn Abi Shayba 18:1182

Abu Bakr narrated to us, he said: Ibn Mahdi narrated to us, from Sufyan, from Ali ibn al-Aqmar, who said: I found a slave of ours who was working in a well in the house of Utbah, so I disputed with him before Shurayh. He (Shurayh) said: "Your evidence that they compelled him, otherwise I will make whoever you wish from the people of the house swear an oath to you."